the men of the tribe dressed and masked to represent the Kachinas in a traditional ceremony.Even though there are male and female Kachinas, only men can represent them.
a masked doll which represents a kachina spirit. They are presented to the women and children of the tribe.
... the left of "=", that will make it a perfect square trinomial of the form x2 + 2xy + y2. Since "2xy" in this case is (b/a)x, we must have y = b/(2a), so we add the square ...